Updated nlohmann::basic_json (markdown)

nlohmann::basic_json.md

@@ -92,9 +92,10 @@ Note the type `json` is a typedef for the class `basic_json` with its default ty
 
 ### Element access
 
+- [**operator[]**](https://github.com/nlohmann/json/wiki/nlohmann::basic_json::operator[])<br>
+  access specific element
 - [**at**](https://github.com/nlohmann/json/wiki/nlohmann::basic_json::at)<br>
-  access specific elements with bound checking
-- `operator[]`
+  access specific element with bound checking
 - [**front**](https://github.com/nlohmann/json/wiki/nlohmann::basic_json::front)<br>
   access the first element
 - [**back**](https://github.com/nlohmann/json/wiki/nlohmann::basic_json::back)<br>